A Guide to SCP: Secure File Transfer on Ubuntu

SCP command examples

The SCP command makes SCP file transfer on Ubuntu simple by letting you securely copy files between computers. The basic format for the SCP command is `scp [options] [user@]source_host:file [user@]destination_host:file`. You can add options to change how the transfer works, like the connection method or port.

The scp command syntax uses the following format:

scp [OPTION] [user@]SRC_HOST:]file1 [user@]DEST_HOST:]file2

• OPTION – scp options that specify cipher, SSH configuration, SSH port, limit, recursive copy, etc.
• [user@]SRC_HOST:]file1 – path to the source file.
• [user@]DEST_HOST:]:file2 – path to the destination file.

The most commonly used options for the SCP command are:

• -P – Specifies the remote host ssh port.
• -p – Preserves file modification and access times.
• -q – Use this option to suppress the progress meter and non-error messages.
• -C – This option forces scp to compress the data as it is sent to the destination machine.
• -r – This option tells scp you to copy directories recursively.

Transferring files

Sending a single file from your computer to another is easy with the SCP command. To move a local file to a remote computer, use a command like `scp [options] /path/to/local/file username@remote:/path/to/destination`. This tells SCP exactly which file to send and where it should end up on the other machine.

scp [options] /path/to/local/file username@remote:/path/to/destination

For example, to transfer a file named `example.txt` from the local machine to a remote machine with the IP address `192.168.0.2`, use the following command:

scp example.txt username@192.168.0.2:/home/username/

To transfer a file from a remote machine to the local machine, use the following command:

scp [options] username@remote:/path/to/file /path/to/destination

For example, to transfer a file named `example.txt` from a remote machine with the IP address `192.168.0.2` to the local machine, use the following command:

scp username@192.168.0.2:/home/username/example.txt /home/localuser/

If you want to save the file under a different name, specify the new file name at the destination. If SSH on the remote host is listening on a port other than the default 22, then you can specify the port using the -P argument:

scp -P 2322 example.txt username@192.168.0.2:/home/username/newName.txt

Transferring directories

Copying a whole folder and everything inside it to another computer is simple with SCP. Use the `-r` option to tell SCP to copy recursively, grabbing the directory and all its contents. The command to complete an SCP transfer of a directory looks like `scp [options] -r /path/to/local/directory username@remote:/path/to/destination`.

scp [options] -r /path/to/local/directory username@remote:/path/to/destination

For example, to transfer a directory named `example` from the local machine to a remote machine with the IP address `192.168.0.2`, use the following command:

scp -r example/ username@192.168.0.2:/home/username/

To transfer a directory from a remote machine to the local machine, use the following command:

scp [options] -r username@remote:/path/to/directory /path/to/destination

For example, to transfer a directory named `example` from a remote machine with the IP address `192.168.0.2` to the local machine, use the following command:

scp -r username@192.168.0.2:/home/username/example/ /home/localuser/

That should do it!

Conclusion:

• Using the SSH protocol, SCP (secure copy) is an essential command-line utility for securely transferring files and directories between networked devices.
• It provides a secure way to transfer files over a network and is particularly useful for protecting sensitive information on insecure networks.
• Understanding the SCP command’s basic syntax and commonly used options is crucial for efficient usage.
• The examples demonstrate transferring files and directories between local and remote machines using SCP on Ubuntu Linux.